<template>
	<view class="uni-numbox">
		<view @click="_calcValue('minus')" class="uni-numbox__minus uni-numbox-btns" :style="{background}">
			<text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue <= min || disabled }" :style="{color}">-</text>
		</view>
		<input :disabled="disabled" @focus="_onFocus" @blur="_onBlur" class="uni-numbox__value" type="number"
			v-model="inputValue" :style="{background, color}" />
		<view @click="_calcValue('plus')" class="uni-numbox__plus uni-numbox-btns" :style="{background}">
			<text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue >= max || disabled }" :style="{color}">+</text>
		</view>
	</view>
</template>
<script>
/**
	 * NumberBox 数字输入框
	 * @description 带加减按钮的数字输入框
	 * @tutorial https://ext.dcloud.net.cn/plugin?id=31
	 * @property {Number} value 输入框当前值
	 * @property {Number} min 最小值
	 * @property {Number} max 最大值
	 * @property {Number} step 每次点击改变的间隔大小
	 * @property {String} background 背景色
	 * @property {String} color 字体颜色（前景色）
	 * @property {Boolean} disabled = [true|false] 是否为禁用状态
	 * @event {Function} change 输入框值改变时触发的事件，参数为输入框当前的 value
	 * @event {Function} focus 输入框聚焦时触发的事件，参数为 event 对象
	 * @event {Function} blur 输入框失焦时触发的事件，参数为 event 对象
	 */

export default {
    name: 'UniNumberBox',
    emits: [ 'change', 'input', 'update:modelValue', 'blur', 'focus' ],
    props: {
        value: {
            type: [ Number, String ],
            default: 1
        },
        modelValue: {
            type: [ Number, String ],
            default: 1
        },
        min: {
            type: Number,
            default: 0
        },
        max: {
            type: Number,
            default: 100
        },
        step: {
            type: Number,
            default: 1
        },
        background: {
            type: String,
            default: '#f5f5f5'
        },
        color: {
            type: String,
            default: '#333'
        },
        disabled: {
            type: Boolean,
            default: false
        }
    },
    data () {
        return {
            inputValue: 0
        }
    },
    watch: {
        value (val) {
            this.inputValue = +val
        },
        modelValue (val) {
            this.inputValue = +val
        }
    },
    created () {
        if (this.value === 1) {
            this.inputValue = +this.modelValue
        }
        if (this.modelValue === 1) {
            this.inputValue = +this.value
        }
    },
    methods: {
        _calcValue (type) {
            if (this.disabled) {
                return
            }
            const scale = this._getDecimalScale()
            let value = this.inputValue * scale
            let step = this.step * scale
            if (type === 'minus') {
                value -= step
                if (value < (this.min * scale)) {
                    return
                }
                if (value > (this.max * scale)) {
                    value = this.max * scale
                }
            }

            if (type === 'plus') {
                value += step
                if (value > (this.max * scale)) {
                    return
                }
                if (value < (this.min * scale)) {
                    value = this.min * scale
                }
            }

            this.inputValue = (value / scale).toFixed(String(scale).length - 1)
            this.$emit('change', +this.inputValue)
            // TODO vue2 兼容
            this.$emit('input', +this.inputValue)
            // TODO vue3 兼容
            this.$emit('update:modelValue', +this.inputValue)
        },
        _getDecimalScale () {

            let scale = 1
            // 浮点型
            if (~~this.step !== this.step) {
                scale = Math.pow(10, String(this.step).split('.')[1].length)
            }
            return scale
        },
        _onBlur (event) {
            this.$emit('blur', event)
            // 官方的代码没有进行数值转换，用户输入的 value 值可能是非法字符：
            // let value = event.detail.value;
            // 将用户输入的内容转化为整数
            let value = parseInt(event.detail.value)

            if (!value) {
                // this.inputValue = 0;
                // 如果转化之后的结果为 NaN，则给定默认值为 1
                this.inputValue = 1
                return
            }
            value = +value
            if (value > this.max) {
                value = this.max
            } else if (value < this.min) {
                value = this.min
            }
            const scale = this._getDecimalScale()
            this.inputValue = value.toFixed(String(scale).length - 1)
            this.$emit('change', +this.inputValue)
            this.$emit('input', +this.inputValue)
        },
        _onFocus (event) {
            this.$emit('focus', event)
        }
    }
}
</script>
<style lang="scss" >
	$box-height: 26px;
	$bg: #f5f5f5;
	$br: 2px;
	$color: #333;

	.uni-numbox {
		/* #ifndef APP-NVUE */
		display: flex;
		/* #endif */
		flex-direction: row;
	}

	.uni-numbox-btns {
		/* #ifndef APP-NVUE */
		display: flex;
		/* #endif */
		flex-direction: row;
		align-items: center;
		justify-content: center;
		padding: 0 8px;
		background-color: $bg;
		/* #ifdef H5 */
		cursor: pointer;
		/* #endif */
	}

	.uni-numbox__value {
		margin: 0 2px;
		background-color: $bg;
		width: 40px;
		height: $box-height;
		text-align: center;
		font-size: 14px;
		border-left-width: 0;
		border-right-width: 0;
		color: $color;
	}

	.uni-numbox__minus {
		border-top-left-radius: $br;
		border-bottom-left-radius: $br;
	}

	.uni-numbox__plus {
		border-top-right-radius: $br;
		border-bottom-right-radius: $br;
	}

	.uni-numbox--text {
		// fix nvue
		line-height: 20px;

		font-size: 20px;
		font-weight: 300;
		color: $color;
	}

	.uni-numbox .uni-numbox--disabled {
		color: #c0c0c0 !important;
		/* #ifdef H5 */
		cursor: not-allowed;
		/* #endif */
	}
</style>
